New Insight Into Antarctic Ice Sheet Properties Using an Improved Teleseismic P-Wave Coda Autocorrelation Method

In the past decades, several gridded datasets of the Antarctic ice sheet have been proposed, which provide important information for detailed modeling of the Antarctic ice sheet. In addition to the radio-echo sounding method, passive seismological methods have become increasingly popular in recent years to reveal ice sheet properties. But the impact of complex subglacial topography on these methods has not been discussed. In this study, the influence of subglacial topography on teleseismic P-wave coda autocorrelation was first analyzed. As the dip angle of the ice-rock interface increased, the time difference caused by the dipping interface became significant. We then demonstrated an approach to estimate the dip parameters of ice bed and ice properties. A test at a pilot station (BYRD) in west Antarctica indicated that the dip parameters estimated by the method are reliable. Finally, it was applied to 65 over-ice stations in three experiments (TAMSEIS, GAMSEIS, and POLENET). Dip parameters of the ice-rock interface were well estimated. The azimuths concurred with those extracted from Bedmap2 and BedMachine, while several dip angles were larger at quite a few stations. The valleys revealed in this study are deeper and the mountains are higher. Our in situ results prove the improvements of BedMachine, but the ice bed slope might have been underestimated in some regions. The single-station passive seismic approach can contribute to new models of the Antarctic ice sheet. The dip parameters and ice sheet properties obtained in this study may assist in other studies, such as ice sheet modeling.